History of Palestine Zionism arrived in Palestine in the late 19th century as a colonialist movement motivated by national impulses. With the backing of Britain, the colonization project expanded and became a solid presence on the land after the war and with the establishment of the British mandate in Palestine (which lasted between 1918 and 1948). This climaxed in a revolt in 1936 against both London and the expanding Zionist colonization project. The revolt, which lasted for three years, failed to sway the British mandate from a policy it had already decided upon in 1917. The British foreign secretary, Lord Balfour, had promised the Zionist leaders that Britain would help the movement to build a homeland for the Jewish people in Palestine. During the 1930s, the Jews were just a quarter of the population, possessing 4 percent of the land. From its early inception and up to the 1930s, Zionist thinkers propagated the need to cleanse the indigenous population of Palestine, if the dream of a Jewish state were to come true. The fact that Israel was let off easily in 1948, and not condemned for the ethnic cleansing it committed, encouraged it to ethnically cleanse a further 300,000 Palestinians from the West Bank and the Gaza strip. The June 1967 war allowed Israel to take the remaining 20 percent of Palestine.